Strain Estimation of Fibronectin Fibrils Using Two Dimensional Digital Image Correlation
Date
2014Metadata
[+] Show full item recordAbstract
Bone consists of a highly specialized mineralized extracellular matrix (ECM)
which supports cells and tissues. Fibronectin is a non-collagenous protein produced by
bone cells and is one of the earliest ECM proteins to be assembled. Fibronectin supports
the assembly of several other bone matrix proteins, therefore understanding the dynamic
process by which the fibronectin is assembled provides insight into how the bone matrix
is formed. Live cell imaging of fibronectin assembly in living osteoblasts helps in
understanding the kinematics of its assembly, which is a highly dynamic process.
Fibronectin assembly was imaged in 2T3 osteoblasts using time lapse imaging
over a 48 hour period. This was divided into four equal 12 hour stages, in which we could
observe the assembly process from no fibrils to formation of a mature fibril network.
Two Dimensional Digital Image Correlation (2D-DIC), a powerful optical computational
tool, was used to quantify the tensile and compressive strains experienced by the
assembling fibronectin fibrils due to the extensive cell motion. The 2D-DIC technique
was used to quantify the total lengths, large strains and displacements of the assembling
fibronectin fibrils. All the code has been developed using Matlab version 12. Seven
iv
different movie stacks from two experiments were analyzed. The results quantify the
strains experienced by the fibrils at different time stages, due to the underlying cell
motion. The average tensile and compression strains were reduced by 6,000με in the12-
24hr movie segment compared to 24-36hr. The average tensile strain was decreased by
6,000 με and the average compression strain was decreased by 3,000με in the 24-36hr
movie segment compared to 36-48hr. This suggests that fibril strains are reduced as a
consequence of matrix maturation. Individual fibrils also showed unique strain profiles,
illustrating both the dynamic nature and heterogeneity of fibril motions. This thesis
signifies the importance of fibronectin protein in the ECM assembly process by providing
strong mathematical and statistical details obtained using the Digital Image Correlation
Table of Contents
Introduction -- Development of the DIC algorithm form measuring fibronectin fibril strains during assembly -- Parametric analysis -- Results and future work
Degree
M.S.